Studies On Promoting Wheat Growth And Controlling Fungal Diseases Of Talaromyces Flavus Strain TF-04

Wheat is one of the most important cereal crops in China.At all stages of growth,it can be infected by pathogenic microorganisms,leading to decrease in the yield and quality,toxin contamination,and serious threat to the food security.At present,the control of wheat diseases mainly relies on chemical agents.But with the increasingly prominent 3R problem,the shortcomings of chemical control are gradually exposed in our vision.In recent years,biocontrol has received widespread attention due to its safety.New biocontrol microorganisms have been continuously explored.In the previous study,a Talaromyces flavus strain TF-04 was identified to promote the growth and enhance disease resistance of rice.To determine whether this strain has a similar promoting effect on the growth and disease resistance of wheat,in this study,the colonization in wheat root,growth promotion and disease resistance of strain TF-04 to wheat were investigated.Besides,mechanisms underlying were also explored.The main results achieved are as follow:1.Fermentation of strain TF-04.Wheat bran,rice husk,rapeseed powder,and other materials were compared as the culture media.It was found that using wheat bran and rice husk with a mass ratio of 1:1 and a moisture content of 65%,strain TF-04 produced the largest number of spores at 28℃.The number of conidia in the dry media could reach up to 1.8×109 cfu/g,which is most suitable for large-scale production.2.Strain TF-04 promotes wheat growth.The plant height,flag leaf length,leaf width,nitrogen(N,20%),phosphorus(P,30%),chlorophyll content(20%),photosynthetic rate(17%),root activity(50%),and thousand grain weight of mature wheat(8%)were significantly increased when wheat seeds were mixed with solid fermentation products of strain TF-04(with a seed to microbial mass ratio of 37.5:1).These results indicate that strain TF-04 promotes wheat growth.3.Strain TF-04 enhances wheat disease resistance.The disease severity of wheat leaf rust in the field was significantly reduced by about 45% compared to the control group wheat seeds were mixed with solid fermentation products of strain TF-04(with a seed to microbial mass ratio of 37.5:1).Three pathogenic fungal strains were isolated from diseased plants with wheat stem rot symptoms using tissue isolation method and identified as Microbacterium majus,Atheria rolfsii,and Fusarium graminearum.It was found that strain TF-04 significantly reduced the disease index of wheat stem rot caused by M.majus and F.graminearum,by approximately 49.53%and 31.03%,respectively.At the same time,strain TF-04 parasitized sclerotia of A.rolfsii.4.Strain TF-04 has multiple mechanisms for promoting growth and disease resistance.Green fluorescent protein labeled strain TF-04 colonizes the roots and stems of wheat.Strain TF-04 solubilized tricalcium phosphate from an initial concentration of 1.74 mg/L to 104.63 mg/L.It had a strong ability to secrete complex iron carriers with a relative content of 88.8% and a strong ability to inhibit pathogenic fungi.In the induction medium,strain TF-04 produced IAA and β-1,3-glucanase.The results suggest that strain TF-04 promote wheat growth and enhance wheat resistance through multiple mechanisms.In summary,strain TF-04 promotes wheat growth and improves disease resistance of wheat.This study provides a beneficial microbial resource with sound application potential for wheat fungal disease biocontrol.